Magnetic Properties of the Mn₅₅Bi₄₅/Nd₂Fe₁₄B Hybrid Magnetic Alloys

The (Mn55Bi45)100−x/(Nd2Fe14B)x hybrid magnetic alloys were prepared by the ball milling of the combined annealed Mn55Bi45 powders and Nd2Fe14B powders. The magnetic properties at room temperature and elevated temperature were investigated. It was found that the saturation magnetization and the coercivity at room temperature increased significantly with the increasing Nd2Fe14B content. The enhanced energy product of 10.8 MGOe and 11.5 MGOe were obtained in (Mn55Bi45)40/(Nd2Fe14B)60 and (Mn55Bi45)20/(Nd2Fe14B)80. At elevated temperatures (350 K), the coercivities of 16.6 kOe and 16.1 kOe were obtained with Nd2Fe14B content of 20 wt.% and 40 wt.%, which were higher than those at room temperature. The temperature coefficients of coercivity of (Mn55Bi45)80/(Nd2Fe14B)20 and (Mn55Bi45)60/(Nd2Fe14B)40 were calculated to be positive, owing to the coercivity temperature characteristics of MnBi alloy. Finally, the energy products remained 10.5 MGOe and 10.1 MGOe in (Mn55Bi45)40/(Nd2Fe14B)60 and (Mn55Bi45)20/(Nd2Fe14B)80 at 350 K, which exhibited potential for high temperature applications